The treatment of thermal and residual stresses in fracture assessments

Abstract The behaviour of a crack under combined mechanical and thermal/residual loads is described in terms of a reference stress or equivalent mechanical loading. The reference stress can be readily established from a knowledge of the stress intensity factor for the thermal/residual load, the magnitude of the mechanical load, and the material stress-strain curve. The result enables the J -integral to be evaluated and is also used to define a procedure for the inclusion of thermal/residual stresses in the CEGB defect assessment method (R6). In particular, a detailed procedure is given for treating thermal/residual stresses in recent revisions of R6 which cater for structures made of materials which strongly work-harden.